Up to now, a disc cartridge, which has rotationally housed therein a disc, such as an optical disc, used as an information recording medium, and which is loaded on a recording and/or reproducing apparatus as the disc is housed therein, has been put to extensive use. This sort of the disc cartridge protects the disc-shaped recording medium by housing it in a cartridge body member, while enabling facilitated insertion/detachment of the disc for a recording and/or reproducing apparatus.
Since the disc cartridge is designed to enable the disc to be loaded on the recording and/or reproducing apparatus, as the disc remains housed in the cartridge body member, there is formed in the cartridge body member a recording and/or reproducing aperture for exposing a part of the disc to outside across the inner and outer rims of the disc. A head part for recording and/or reproduction, such as an optical pickup, mounted to the recording and/or reproducing apparatus, faces the disc via this recording and/or reproducing aperture, and scans the signal recording area of the disc to record and/or reproduce the information signals.
Thus, the disc cartridge, having the disc housed therein, is provided with a shutter member for closing the recording and/or reproducing aperture. This shutter member includes a rectangular flat-plate shaped shutter part, having the dimension sufficient to close the recording and/or reproducing aperture, and a support part 101 of a U-shaped cross-section, formed towards the proximal end of the shutter part. The shutter member has its support part introduced into a groove-shaped slide guide formed in the cartridge body unit, and hence the shutter member is slidable along a lateral surface of the cartridge body unit. In this manner, the shutter member may be slid so that its shutter part may open/close the recording and/or reproducing aperture.
The shutter member includes, in a side of the support part thereof facing a lateral side of the cartridge body unit, a shutter opening/closing opening into which is inserted a shutter opening/closing member 100 adapted for opening/closing the shutter member. This shutter opening/closing member, introduced into the shutter opening/closing opening, is provided to a main apparatus body unit of the disc recording and/or reproducing apparatus, and is formed by, for example, an elastic spring, exhibiting the flexibility. Referring to FIG. 20, the shutter opening/closing member 100 includes a substantially chevron-shaped retention part 102 protruded on the movement trajectory of the shutter member for holding the so intruded disc cartridge in order to watch the intrusion of the disc cartridge. As the cartridge body unit is transported, this retention part 102 is abutted against the foremost part of the support part 101 of the shutter member to flex the shutter opening/closing member 100. Thus, the shutter opening/closing member rides on the support part 101 to be slid thereon for intrusion into and engagement with the shutter opening/closing opening.
In this manner, the shutter opening/closing opening is regulated in the movement thereof along the slide guide part provided to the cartridge body unit to inhibit intrusion of the shutter member into the main apparatus body unit. Hence, the shutter member is moved relative to the cartridge body unit of the disc cartridge transported further into the main apparatus body unit, thereby opening the recording and/or reproducing aperture. When the disc cartridge is moved in the direction of being ejected from the disc recording and/or reproducing apparatus, the shutter member, engaged by the shutter opening/closing member 100 and thereby prohibited from being moved further, is moved relative to the cartridge body unit of the disc cartridge being transported to outside the main apparatus body unit, such as to close the recording and/or reproducing opening. When the cartridge body unit is ejected to outside the recording and/or reproducing apparatus, the shutter opening/closing member 100 is flexed to outside the cartridge body unit, due to the sliding of the shutter opening/closing opening, and hence the retention part is receded from the shutter opening/closing opening.
With the above-described state-of-the art disc cartridge, the foremost part of the support part 101 of the shutter member, which is the contact point of the shutter opening/closing member 100 with the shutter member, is square-shaped, with the consequence that the retention part 102 is abutted against the distal end of the support part 101 to interfere with smooth insertion and worsen the sense of insertion of the disc cartridge. In addition, the retention part 102 of the shutter opening/closing member 100 and the support part 101 of the shutter member, colliding against each other, tend to deteriorate or cause wear of the two components, while dust and dirt also tend to be produced.